In daily work routines of police officers, situations may occur that have not been trained previously because of high costs, because of the danger, time or effort involved. But some knowledge-in-use is required to respond adequately to these complex situations, thus virtual training seems to be the obvious choice. In order to develop a virtual training environment, we need an understanding of the underlying learning processes. This paper explicates a theory-driven design process of a virtual training environment and its application in a German state police department. We conceptualize how the acquisition of knowledge-in-use in virtual training environments takes place and focus on what is possible in virtual training.